drivers/rtc/rtc-ds1307.c

   1 /*
   2  * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
   3  *
   4  *  Copyright (C) 2005 James Chapman (ds1337 core)
   5  *  Copyright (C) 2006 David Brownell
   6  *  Copyright (C) 2009 Matthias Fuchs (rx8025 support)
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/slab.h>
  16 #include <linux/i2c.h>
  17 #include <linux/string.h>
  18 #include <linux/rtc.h>
  19 #include <linux/bcd.h>
  20
  21
  22
  23 /* We can't determine type by probing, but if we expect pre-Linux code
  24  * to have set the chip up as a clock (turning on the oscillator and
  25  * setting the date and time), Linux can ignore the non-clock features.
  26  * That's a natural job for a factory or repair bench.
  27  */
  28 enum ds_type {
  29         ds_1307,
  30         ds_1337,
  31         ds_1338,
  32         ds_1339,
  33         ds_1340,
  34         ds_1388,
  35         ds_3231,
  36         m41t00,
  37         mcp7941x,
  38         rx_8025,
  39         // rs5c372 too?  different address...
  40 };
  41
  42
  43 /* RTC registers don't differ much, except for the century flag */
  44 #define DS1307_REG_SECS         0x00    /* 00-59 */
  45 #       define DS1307_BIT_CH            0x80
  46 #       define DS1340_BIT_nEOSC         0x80
  47 #       define MCP7941X_BIT_ST          0x80
  48 #define DS1307_REG_MIN          0x01    /* 00-59 */
  49 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
  50 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
  51 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
  52 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
  53 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
  54 #define DS1307_REG_WDAY         0x03    /* 01-07 */
  55 #       define MCP7941X_BIT_VBATEN      0x08
  56 #define DS1307_REG_MDAY         0x04    /* 01-31 */
  57 #define DS1307_REG_MONTH        0x05    /* 01-12 */
  58 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
  59 #define DS1307_REG_YEAR         0x06    /* 00-99 */
  60
  61 /* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  62  * start at 7, and they differ a LOT. Only control and status matter for
  63  * basic RTC date and time functionality; be careful using them.
  64  */
  65 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
  66 #       define DS1307_BIT_OUT           0x80
  67 #       define DS1338_BIT_OSF           0x20
  68 #       define DS1307_BIT_SQWE          0x10
  69 #       define DS1307_BIT_RS1           0x02
  70 #       define DS1307_BIT_RS0           0x01
  71 #define DS1337_REG_CONTROL      0x0e
  72 #       define DS1337_BIT_nEOSC         0x80
  73 #       define DS1339_BIT_BBSQI         0x20
  74 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
  75 #       define DS1337_BIT_RS2           0x10
  76 #       define DS1337_BIT_RS1           0x08
  77 #       define DS1337_BIT_INTCN         0x04
  78 #       define DS1337_BIT_A2IE          0x02
  79 #       define DS1337_BIT_A1IE          0x01
  80 #define DS1340_REG_CONTROL      0x07
  81 #       define DS1340_BIT_OUT           0x80
  82 #       define DS1340_BIT_FT            0x40
  83 #       define DS1340_BIT_CALIB_SIGN    0x20
  84 #       define DS1340_M_CALIBRATION     0x1f
  85 #define DS1340_REG_FLAG         0x09
  86 #       define DS1340_BIT_OSF           0x80
  87 #define DS1337_REG_STATUS       0x0f
  88 #       define DS1337_BIT_OSF           0x80
  89 #       define DS1337_BIT_A2I           0x02
  90 #       define DS1337_BIT_A1I           0x01
  91 #define DS1339_REG_ALARM1_SECS  0x07
  92 #define DS1339_REG_TRICKLE      0x10
  93
  94 #define RX8025_REG_CTRL1        0x0e
  95 #       define RX8025_BIT_2412          0x20
  96 #define RX8025_REG_CTRL2        0x0f
  97 #       define RX8025_BIT_PON           0x10
  98 #       define RX8025_BIT_VDET          0x40
  99 #       define RX8025_BIT_XST           0x20
 100
 101
 102 struct ds1307 {
 103         u8                      offset; /* register's offset */
 104         u8                      regs[11];
 105         enum ds_type            type;
 106         unsigned long           flags;
 107 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
 108 #define HAS_ALARM       1               /* bit 1 == irq claimed */
 109         struct i2c_client       *client;
 110         struct rtc_device       *rtc;
 111         struct work_struct      work;
 112         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 113                                u8 length, u8 *values);
 114         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 115                                 u8 length, const u8 *values);
 116 };
 117
 118 struct chip_desc {
 119         unsigned                nvram56:1;
 120         unsigned                alarm:1;
 121 };
 122
 123 static const struct chip_desc chips[] = {
 124 [ds_1307] = {
 125         .nvram56        = 1,
 126 },
 127 [ds_1337] = {
 128         .alarm          = 1,
 129 },
 130 [ds_1338] = {
 131         .nvram56        = 1,
 132 },
 133 [ds_1339] = {
 134         .alarm          = 1,
 135 },
 136 [ds_1340] = {
 137 },
 138 [ds_3231] = {
 139         .alarm          = 1,
 140 },
 141 [m41t00] = {
 142 },
 143 [mcp7941x] = {
 144 },
 145 [rx_8025] = {
 146 }, };
 147
 148 static const struct i2c_device_id ds1307_id[] = {
 149         { "ds1307", ds_1307 },
 150         { "ds1337", ds_1337 },
 151         { "ds1338", ds_1338 },
 152         { "ds1339", ds_1339 },
 153         { "ds1388", ds_1388 },
 154         { "ds1340", ds_1340 },
 155         { "ds3231", ds_3231 },
 156         { "m41t00", m41t00 },
 157         { "mcp7941x", mcp7941x },
 158         { "pt7c4338", ds_1307 },
 159         { "rx8025", rx_8025 },
 160         { }
 161 };
 162 MODULE_DEVICE_TABLE(i2c, ds1307_id);
 163
 164 /*----------------------------------------------------------------------*/
 165
 166 #define BLOCK_DATA_MAX_TRIES 10
 167
 168 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
 169                                        u8 command, u8 length, u8 *values)
 170 {
 171         s32 i, data;
 172
 173         for (i = 0; i < length; i++) {
 174                 data = i2c_smbus_read_byte_data(client, command + i);
 175                 if (data < 0)
 176                         return data;
 177                 values[i] = data;
 178         }
 179         return i;
 180 }
 181
 182 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
 183                                   u8 length, u8 *values)
 184 {
 185         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
 186         s32 ret;
 187         int tries = 0;
 188
 189         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
 190         ret = ds1307_read_block_data_once(client, command, length, values);
 191         if (ret < 0)
 192                 return ret;
 193         do {
 194                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 195                         dev_err(&client->dev,
 196                                 "ds1307_read_block_data failed\n");
 197                         return -EIO;
 198                 }
 199                 memcpy(oldvalues, values, length);
 200                 ret = ds1307_read_block_data_once(client, command, length,
 201                                                   values);
 202                 if (ret < 0)
 203                         return ret;
 204         } while (memcmp(oldvalues, values, length));
 205         return length;
 206 }
 207
 208 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
 209                                    u8 length, const u8 *values)
 210 {
 211         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
 212         int tries = 0;
 213
 214         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
 215         do {
 216                 s32 i, ret;
 217
 218                 if (++tries > BLOCK_DATA_MAX_TRIES) {
 219                         dev_err(&client->dev,
 220                                 "ds1307_write_block_data failed\n");
 221                         return -EIO;
 222                 }
 223                 for (i = 0; i < length; i++) {
 224                         ret = i2c_smbus_write_byte_data(client, command + i,
 225                                                         values[i]);
 226                         if (ret < 0)
 227                                 return ret;
 228                 }
 229                 ret = ds1307_read_block_data_once(client, command, length,
 230                                                   currvalues);
 231                 if (ret < 0)
 232                         return ret;
 233         } while (memcmp(currvalues, values, length));
 234         return length;
 235 }
 236
 237 /*----------------------------------------------------------------------*/
 238
 239 /*
 240  * The IRQ logic includes a "real" handler running in IRQ context just
 241  * long enough to schedule this workqueue entry.   We need a task context
 242  * to talk to the RTC, since I2C I/O calls require that; and disable the
 243  * IRQ until we clear its status on the chip, so that this handler can
 244  * work with any type of triggering (not just falling edge).
 245  *
 246  * The ds1337 and ds1339 both have two alarms, but we only use the first
 247  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
 248  * signal; ds1339 chips have only one alarm signal.
 249  */
 250 static void ds1307_work(struct work_struct *work)
 251 {
 252         struct ds1307           *ds1307;
 253         struct i2c_client       *client;
 254         struct mutex            *lock;
 255         int                     stat, control;
 256
 257         ds1307 = container_of(work, struct ds1307, work);
 258         client = ds1307->client;
 259         lock = &ds1307->rtc->ops_lock;
 260
 261         mutex_lock(lock);
 262         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
 263         if (stat < 0)
 264                 goto out;
 265
 266         if (stat & DS1337_BIT_A1I) {
 267                 stat &= ~DS1337_BIT_A1I;
 268                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
 269
 270                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 271                 if (control < 0)
 272                         goto out;
 273
 274                 control &= ~DS1337_BIT_A1IE;
 275                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
 276
 277                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 278         }
 279
 280 out:
 281         if (test_bit(HAS_ALARM, &ds1307->flags))
 282                 enable_irq(client->irq);
 283         mutex_unlock(lock);
 284 }
 285
 286 static irqreturn_t ds1307_irq(int irq, void *dev_id)
 287 {
 288         struct i2c_client       *client = dev_id;
 289         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 290
 291         disable_irq_nosync(irq);
 292         schedule_work(&ds1307->work);
 293         return IRQ_HANDLED;
 294 }
 295
 296 /*----------------------------------------------------------------------*/
 297
 298 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 299 {
 300         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 301         int             tmp;
 302
 303         /* read the RTC date and time registers all at once */
 304         tmp = ds1307->read_block_data(ds1307->client,
 305                 ds1307->offset, 7, ds1307->regs);
 306         if (tmp != 7) {
 307                 dev_err(dev, "%s error %d\n", "read", tmp);
 308                 return -EIO;
 309         }
 310
 311         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 312                         "read",
 313                         ds1307->regs[0], ds1307->regs[1],
 314                         ds1307->regs[2], ds1307->regs[3],
 315                         ds1307->regs[4], ds1307->regs[5],
 316                         ds1307->regs[6]);
 317
 318         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
 319         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
 320         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
 321         t->tm_hour = bcd2bin(tmp);
 322         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
 323         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
 324         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
 325         t->tm_mon = bcd2bin(tmp) - 1;
 326
 327         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
 328         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 329
 330         dev_dbg(dev, "%s secs=%d, mins=%d, "
 331                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 332                 "read", t->tm_sec, t->tm_min,
 333                 t->tm_hour, t->tm_mday,
 334                 t->tm_mon, t->tm_year, t->tm_wday);
 335
 336         /* initial clock setting can be undefined */
 337         return rtc_valid_tm(t);
 338 }
 339
 340 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 341 {
 342         struct ds1307   *ds1307 = dev_get_drvdata(dev);
 343         int             result;
 344         int             tmp;
 345         u8              *buf = ds1307->regs;
 346
 347         dev_dbg(dev, "%s secs=%d, mins=%d, "
 348                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 349                 "write", t->tm_sec, t->tm_min,
 350                 t->tm_hour, t->tm_mday,
 351                 t->tm_mon, t->tm_year, t->tm_wday);
 352
 353         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 354         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 355         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 356         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 357         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 358         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 359
 360         /* assume 20YY not 19YY */
 361         tmp = t->tm_year - 100;
 362         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 363
 364         switch (ds1307->type) {
 365         case ds_1337:
 366         case ds_1339:
 367         case ds_3231:
 368                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
 369                 break;
 370         case ds_1340:
 371                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
 372                                 | DS1340_BIT_CENTURY;
 373                 break;
 374         case mcp7941x:
 375                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
 376                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
 377                 break;
 378         default:
 379                 break;
 380         }
 381
 382         dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
 383                 "write", buf[0], buf[1], buf[2], buf[3],
 384                 buf[4], buf[5], buf[6]);
 385
 386         result = ds1307->write_block_data(ds1307->client,
 387                 ds1307->offset, 7, buf);
 388         if (result < 0) {
 389                 dev_err(dev, "%s error %d\n", "write", result);
 390                 return result;
 391         }
 392         return 0;
 393 }
 394
 395 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 396 {
 397         struct i2c_client       *client = to_i2c_client(dev);
 398         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 399         int                     ret;
 400
 401         if (!test_bit(HAS_ALARM, &ds1307->flags))
 402                 return -EINVAL;
 403
 404         /* read all ALARM1, ALARM2, and status registers at once */
 405         ret = ds1307->read_block_data(client,
 406                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
 407         if (ret != 9) {
 408                 dev_err(dev, "%s error %d\n", "alarm read", ret);
 409                 return -EIO;
 410         }
 411
 412         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 413                         "alarm read",
 414                         ds1307->regs[0], ds1307->regs[1],
 415                         ds1307->regs[2], ds1307->regs[3],
 416                         ds1307->regs[4], ds1307->regs[5],
 417                         ds1307->regs[6], ds1307->regs[7],
 418                         ds1307->regs[8]);
 419
 420         /* report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 421          * and that all four fields are checked matches
 422          */
 423         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
 424         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
 425         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
 426         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
 427         t->time.tm_mon = -1;
 428         t->time.tm_year = -1;
 429         t->time.tm_wday = -1;
 430         t->time.tm_yday = -1;
 431         t->time.tm_isdst = -1;
 432
 433         /* ... and status */
 434         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
 435         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
 436
 437         dev_dbg(dev, "%s secs=%d, mins=%d, "
 438                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 439                 "alarm read", t->time.tm_sec, t->time.tm_min,
 440                 t->time.tm_hour, t->time.tm_mday,
 441                 t->enabled, t->pending);
 442
 443         return 0;
 444 }
 445
 446 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 447 {
 448         struct i2c_client       *client = to_i2c_client(dev);
 449         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 450         unsigned char           *buf = ds1307->regs;
 451         u8                      control, status;
 452         int                     ret;
 453
 454         if (!test_bit(HAS_ALARM, &ds1307->flags))
 455                 return -EINVAL;
 456
 457         dev_dbg(dev, "%s secs=%d, mins=%d, "
 458                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
 459                 "alarm set", t->time.tm_sec, t->time.tm_min,
 460                 t->time.tm_hour, t->time.tm_mday,
 461                 t->enabled, t->pending);
 462
 463         /* read current status of both alarms and the chip */
 464         ret = ds1307->read_block_data(client,
 465                         DS1339_REG_ALARM1_SECS, 9, buf);
 466         if (ret != 9) {
 467                 dev_err(dev, "%s error %d\n", "alarm write", ret);
 468                 return -EIO;
 469         }
 470         control = ds1307->regs[7];
 471         status = ds1307->regs[8];
 472
 473         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
 474                         "alarm set (old status)",
 475                         ds1307->regs[0], ds1307->regs[1],
 476                         ds1307->regs[2], ds1307->regs[3],
 477                         ds1307->regs[4], ds1307->regs[5],
 478                         ds1307->regs[6], control, status);
 479
 480         /* set ALARM1, using 24 hour and day-of-month modes */
 481         buf[0] = bin2bcd(t->time.tm_sec);
 482         buf[1] = bin2bcd(t->time.tm_min);
 483         buf[2] = bin2bcd(t->time.tm_hour);
 484         buf[3] = bin2bcd(t->time.tm_mday);
 485
 486         /* set ALARM2 to non-garbage */
 487         buf[4] = 0;
 488         buf[5] = 0;
 489         buf[6] = 0;
 490
 491         /* optionally enable ALARM1 */
 492         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 493         if (t->enabled) {
 494                 dev_dbg(dev, "alarm IRQ armed\n");
 495                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
 496         }
 497         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 498
 499         ret = ds1307->write_block_data(client,
 500                         DS1339_REG_ALARM1_SECS, 9, buf);
 501         if (ret < 0) {
 502                 dev_err(dev, "can't set alarm time\n");
 503                 return ret;
 504         }
 505
 506         return 0;
 507 }
 508
 509 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 510 {
 511         struct i2c_client       *client = to_i2c_client(dev);
 512         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 513         int                     ret;
 514
 515         if (!test_bit(HAS_ALARM, &ds1307->flags))
 516                 return -ENOTTY;
 517
 518         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
 519         if (ret < 0)
 520                 return ret;
 521
 522         if (enabled)
 523                 ret |= DS1337_BIT_A1IE;
 524         else
 525                 ret &= ~DS1337_BIT_A1IE;
 526
 527         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
 528         if (ret < 0)
 529                 return ret;
 530
 531         return 0;
 532 }
 533
 534 static const struct rtc_class_ops ds13xx_rtc_ops = {
 535         .read_time      = ds1307_get_time,
 536         .set_time       = ds1307_set_time,
 537         .read_alarm     = ds1337_read_alarm,
 538         .set_alarm      = ds1337_set_alarm,
 539         .alarm_irq_enable = ds1307_alarm_irq_enable,
 540 };
 541
 542 /*----------------------------------------------------------------------*/
 543
 544 #define NVRAM_SIZE      56
 545
 546 static ssize_t
 547 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
 548                 struct bin_attribute *attr,
 549                 char *buf, loff_t off, size_t count)
 550 {
 551         struct i2c_client       *client;
 552         struct ds1307           *ds1307;
 553         int                     result;
 554
 555         client = kobj_to_i2c_client(kobj);
 556         ds1307 = i2c_get_clientdata(client);
 557
 558         if (unlikely(off >= NVRAM_SIZE))
 559                 return 0;
 560         if ((off + count) > NVRAM_SIZE)
 561                 count = NVRAM_SIZE - off;
 562         if (unlikely(!count))
 563                 return count;
 564
 565         result = ds1307->read_block_data(client, 8 + off, count, buf);
 566         if (result < 0)
 567                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
 568         return result;
 569 }
 570
 571 static ssize_t
 572 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 573                 struct bin_attribute *attr,
 574                 char *buf, loff_t off, size_t count)
 575 {
 576         struct i2c_client       *client;
 577         struct ds1307           *ds1307;
 578         int                     result;
 579
 580         client = kobj_to_i2c_client(kobj);
 581         ds1307 = i2c_get_clientdata(client);
 582
 583         if (unlikely(off >= NVRAM_SIZE))
 584                 return -EFBIG;
 585         if ((off + count) > NVRAM_SIZE)
 586                 count = NVRAM_SIZE - off;
 587         if (unlikely(!count))
 588                 return count;
 589
 590         result = ds1307->write_block_data(client, 8 + off, count, buf);
 591         if (result < 0) {
 592                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
 593                 return result;
 594         }
 595         return count;
 596 }
 597
 598 static struct bin_attribute nvram = {
 599         .attr = {
 600                 .name   = "nvram",
 601                 .mode   = S_IRUGO | S_IWUSR,
 602         },
 603
 604         .read   = ds1307_nvram_read,
 605         .write  = ds1307_nvram_write,
 606         .size   = NVRAM_SIZE,
 607 };
 608
 609 /*----------------------------------------------------------------------*/
 610
 611 static struct i2c_driver ds1307_driver;
 612
 613 static int __devinit ds1307_probe(struct i2c_client *client,
 614                                   const struct i2c_device_id *id)
 615 {
 616         struct ds1307           *ds1307;
 617         int                     err = -ENODEV;
 618         int                     tmp;
 619         const struct chip_desc  *chip = &chips[id->driver_data];
 620         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
 621         int                     want_irq = false;
 622         unsigned char           *buf;
 623         static const int        bbsqi_bitpos[] = {
 624                 [ds_1337] = 0,
 625                 [ds_1339] = DS1339_BIT_BBSQI,
 626                 [ds_3231] = DS3231_BIT_BBSQW,
 627         };
 628
 629         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
 630             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 631                 return -EIO;
 632
 633         if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
 634                 return -ENOMEM;
 635
 636         i2c_set_clientdata(client, ds1307);
 637
 638         ds1307->client  = client;
 639         ds1307->type    = id->driver_data;
 640         ds1307->offset  = 0;
 641
 642         buf = ds1307->regs;
 643         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
 644                 ds1307->read_block_data = i2c_smbus_read_i2c_block_data;
 645                 ds1307->write_block_data = i2c_smbus_write_i2c_block_data;
 646         } else {
 647                 ds1307->read_block_data = ds1307_read_block_data;
 648                 ds1307->write_block_data = ds1307_write_block_data;
 649         }
 650
 651         switch (ds1307->type) {
 652         case ds_1337:
 653         case ds_1339:
 654         case ds_3231:
 655                 /* has IRQ? */
 656                 if (ds1307->client->irq > 0 && chip->alarm) {
 657                         INIT_WORK(&ds1307->work, ds1307_work);
 658                         want_irq = true;
 659                 }
 660                 /* get registers that the "rtc" read below won't read... */
 661                 tmp = ds1307->read_block_data(ds1307->client,
 662                                 DS1337_REG_CONTROL, 2, buf);
 663                 if (tmp != 2) {
 664                         pr_debug("read error %d\n", tmp);
 665                         err = -EIO;
 666                         goto exit_free;
 667                 }
 668
 669                 /* oscillator off?  turn it on, so clock can tick. */
 670                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 671                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 672
 673                 /* Using IRQ?  Disable the square wave and both alarms.
 674                  * For some variants, be sure alarms can trigger when we're
 675                  * running on Vbackup (BBSQI/BBSQW)
 676                  */
 677                 if (want_irq) {
 678                         ds1307->regs[0] |= DS1337_BIT_INTCN
 679                                         | bbsqi_bitpos[ds1307->type];
 680                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
 681                 }
 682
 683                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
 684                                                         ds1307->regs[0]);
 685
 686                 /* oscillator fault?  clear flag, and warn */
 687                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
 688                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
 689                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
 690                         dev_warn(&client->dev, "SET TIME!\n");
 691                 }
 692                 break;
 693
 694         case rx_8025:
 695                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 696                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 697                 if (tmp != 2) {
 698                         pr_debug("read error %d\n", tmp);
 699                         err = -EIO;
 700                         goto exit_free;
 701                 }
 702
 703                 /* oscillator off?  turn it on, so clock can tick. */
 704                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
 705                         ds1307->regs[1] |= RX8025_BIT_XST;
 706                         i2c_smbus_write_byte_data(client,
 707                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 708                                                   ds1307->regs[1]);
 709                         dev_warn(&client->dev,
 710                                  "oscillator stop detected - SET TIME!\n");
 711                 }
 712
 713                 if (ds1307->regs[1] & RX8025_BIT_PON) {
 714                         ds1307->regs[1] &= ~RX8025_BIT_PON;
 715                         i2c_smbus_write_byte_data(client,
 716                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 717                                                   ds1307->regs[1]);
 718                         dev_warn(&client->dev, "power-on detected\n");
 719                 }
 720
 721                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
 722                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
 723                         i2c_smbus_write_byte_data(client,
 724                                                   RX8025_REG_CTRL2 << 4 | 0x08,
 725                                                   ds1307->regs[1]);
 726                         dev_warn(&client->dev, "voltage drop detected\n");
 727                 }
 728
 729                 /* make sure we are running in 24hour mode */
 730                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
 731                         u8 hour;
 732
 733                         /* switch to 24 hour mode */
 734                         i2c_smbus_write_byte_data(client,
 735                                                   RX8025_REG_CTRL1 << 4 | 0x08,
 736                                                   ds1307->regs[0] |
 737                                                   RX8025_BIT_2412);
 738
 739                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
 740                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
 741                         if (tmp != 2) {
 742                                 pr_debug("read error %d\n", tmp);
 743                                 err = -EIO;
 744                                 goto exit_free;
 745                         }
 746
 747                         /* correct hour */
 748                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
 749                         if (hour == 12)
 750                                 hour = 0;
 751                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 752                                 hour += 12;
 753
 754                         i2c_smbus_write_byte_data(client,
 755                                                   DS1307_REG_HOUR << 4 | 0x08,
 756                                                   hour);
 757                 }
 758                 break;
 759         case ds_1388:
 760                 ds1307->offset = 1; /* Seconds starts at 1 */
 761                 break;
 762         default:
 763                 break;
 764         }
 765
 766 read_rtc:
 767         /* read RTC registers */
 768         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
 769         if (tmp != 8) {
 770                 pr_debug("read error %d\n", tmp);
 771                 err = -EIO;
 772                 goto exit_free;
 773         }
 774
 775         /* minimal sanity checking; some chips (like DS1340) don't
 776          * specify the extra bits as must-be-zero, but there are
 777          * still a few values that are clearly out-of-range.
 778          */
 779         tmp = ds1307->regs[DS1307_REG_SECS];
 780         switch (ds1307->type) {
 781         case ds_1307:
 782         case m41t00:
 783                 /* clock halted?  turn it on, so clock can tick. */
 784                 if (tmp & DS1307_BIT_CH) {
 785                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 786                         dev_warn(&client->dev, "SET TIME!\n");
 787                         goto read_rtc;
 788                 }
 789                 break;
 790         case ds_1338:
 791                 /* clock halted?  turn it on, so clock can tick. */
 792                 if (tmp & DS1307_BIT_CH)
 793                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 794
 795                 /* oscillator fault?  clear flag, and warn */
 796                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
 797                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
 798                                         ds1307->regs[DS1307_REG_CONTROL]
 799                                         & ~DS1338_BIT_OSF);
 800                         dev_warn(&client->dev, "SET TIME!\n");
 801                         goto read_rtc;
 802                 }
 803                 break;
 804         case ds_1340:
 805                 /* clock halted?  turn it on, so clock can tick. */
 806                 if (tmp & DS1340_BIT_nEOSC)
 807                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
 808
 809                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
 810                 if (tmp < 0) {
 811                         pr_debug("read error %d\n", tmp);
 812                         err = -EIO;
 813                         goto exit_free;
 814                 }
 815
 816                 /* oscillator fault?  clear flag, and warn */
 817                 if (tmp & DS1340_BIT_OSF) {
 818                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
 819                         dev_warn(&client->dev, "SET TIME!\n");
 820                 }
 821                 break;
 822         case mcp7941x:
 823                 /* make sure that the backup battery is enabled */
 824                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
 825                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
 826                                         ds1307->regs[DS1307_REG_WDAY]
 827                                         | MCP7941X_BIT_VBATEN);
 828                 }
 829
 830                 /* clock halted?  turn it on, so clock can tick. */
 831                 if (!(tmp & MCP7941X_BIT_ST)) {
 832                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
 833                                         MCP7941X_BIT_ST);
 834                         dev_warn(&client->dev, "SET TIME!\n");
 835                         goto read_rtc;
 836                 }
 837
 838                 break;
 839         case rx_8025:
 840         case ds_1337:
 841         case ds_1339:
 842         case ds_1388:
 843         case ds_3231:
 844                 break;
 845         }
 846
 847         tmp = ds1307->regs[DS1307_REG_HOUR];
 848         switch (ds1307->type) {
 849         case ds_1340:
 850         case m41t00:
 851                 /* NOTE: ignores century bits; fix before deploying
 852                  * systems that will run through year 2100.
 853                  */
 854                 break;
 855         case rx_8025:
 856                 break;
 857         default:
 858                 if (!(tmp & DS1307_BIT_12HR))
 859                         break;
 860
 861                 /* Be sure we're in 24 hour mode.  Multi-master systems
 862                  * take note...
 863                  */
 864                 tmp = bcd2bin(tmp & 0x1f);
 865                 if (tmp == 12)
 866                         tmp = 0;
 867                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
 868                         tmp += 12;
 869                 i2c_smbus_write_byte_data(client,
 870                                 ds1307->offset + DS1307_REG_HOUR,
 871                                 bin2bcd(tmp));
 872         }
 873
 874         ds1307->rtc = rtc_device_register(client->name, &client->dev,
 875                                 &ds13xx_rtc_ops, THIS_MODULE);
 876         if (IS_ERR(ds1307->rtc)) {
 877                 err = PTR_ERR(ds1307->rtc);
 878                 dev_err(&client->dev,
 879                         "unable to register the class device\n");
 880                 goto exit_free;
 881         }
 882
 883         if (want_irq) {
 884                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
 885                           ds1307->rtc->name, client);
 886                 if (err) {
 887                         dev_err(&client->dev,
 888                                 "unable to request IRQ!\n");
 889                         goto exit_irq;
 890                 }
 891
 892                 device_set_wakeup_capable(&client->dev, 1);
 893                 set_bit(HAS_ALARM, &ds1307->flags);
 894                 dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
 895         }
 896
 897         if (chip->nvram56) {
 898                 err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
 899                 if (err == 0) {
 900                         set_bit(HAS_NVRAM, &ds1307->flags);
 901                         dev_info(&client->dev, "56 bytes nvram\n");
 902                 }
 903         }
 904
 905         return 0;
 906
 907 exit_irq:
 908         rtc_device_unregister(ds1307->rtc);
 909 exit_free:
 910         kfree(ds1307);
 911         return err;
 912 }
 913
 914 static int __devexit ds1307_remove(struct i2c_client *client)
 915 {
 916         struct ds1307           *ds1307 = i2c_get_clientdata(client);
 917
 918         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
 919                 free_irq(client->irq, client);
 920                 cancel_work_sync(&ds1307->work);
 921         }
 922
 923         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
 924                 sysfs_remove_bin_file(&client->dev.kobj, &nvram);
 925
 926         rtc_device_unregister(ds1307->rtc);
 927         kfree(ds1307);
 928         return 0;
 929 }
 930
 931 static struct i2c_driver ds1307_driver = {
 932         .driver = {
 933                 .name   = "rtc-ds1307",
 934                 .owner  = THIS_MODULE,
 935         },
 936         .probe          = ds1307_probe,
 937         .remove         = __devexit_p(ds1307_remove),
 938         .id_table       = ds1307_id,
 939 };
 940
 941 static int __init ds1307_init(void)
 942 {
 943         return i2c_add_driver(&ds1307_driver);
 944 }
 945 module_init(ds1307_init);
 946
 947 static void __exit ds1307_exit(void)
 948 {
 949         i2c_del_driver(&ds1307_driver);
 950 }
 951 module_exit(ds1307_exit);
 952
 953 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
 954 MODULE_LICENSE("GPL");